Rocketwise propelled projectiles of the unguided type



Jan. 21, 1964 E. T. J. DAVIES ETAL 3,118,377

ROCKETWISE PROPELLED PROJECTILES OF THE UNGUIDED TYPE Filed July 22, 1958 FIG. 2.

FIG. I

Inventqn; fr/c 712' pa V185 Reyzbak/ J Home United States Patent Gt 3 118 577 RJCKETWISE PRGPEiLElD FRGEEQTHLE 6F THE UNGUFJEE TYPE The present invention relates to improvements in rocketwise propelled projectiles of the unguided type, and an object of the invention is to achieve greater directional accuracy with such projectiles.

In the case of projectiles of the type just mentioned, the projectile has been propelled, at least after it has left the device from which it is tired, by a motor consisting of a charge of ignited material which creates a considerable pressure of gas which escapes from the rear of the projectile in the form of one or more jets and thus eliects the propelling action. it has heretofore been the practice to create as great a volume of propulsive gas as possible in a very short space of time and the result of this has been that at some part of the trajectory preceding the vertex the projectile has travelled at a very high maximum speed.

It is well known that, as the speed of a projectile is increased, the drag, due to the action of the air, not only becomes greater, but its rate of increase is greater than any rate of increase in the velocity of the projectile. Moreover, in the case of spin-stabilised projectiles, the requisite speed of spin is a function of the maximum speed of travel of the projectile, as well as of its length; consequently, when it is desired to increase the speed of travel and/ or the length of the rocket, it is necessary also to increase the speed of spin to maintain stability.

The present invention makes provision whereby, in an unguided rocltetwise propelled projectile, the motor acts to propel the projectile at a substantially constant speed which is such that the drag does not reach an excessive value and, in the case of a spin-stabilised projectile, permits a lower speed of spin to be employed for stabilisation of a given length of projectile. This permissible reduction in speed of spin for a given length of projectile permits a greater length of projectile to be used at, for example, the speed of spin heretofore required, with the result that the projectile can carry a greater propulsive charge and therefore travel a correspondingly greater distance. Accordingly, the rocket may comprise a booster charge which is sufiicient to ensure acceleration of the rocket to a velocity within predetermined limits and a second, independently combustible, charge whic will act at a rate sufficient only to sustain the velocity of the rocket within these limits.

The booster charge may be hollow and the second charge may be disposed concentrically within this hollow booster charge and of such size relative thereto as to provide an annular combustion space between. itself and the booster charge. The booster and second charges may, in fact, be contained in concentric casings, the casing containing the second charge being of a diameter such as to form with the booster charge an annular combustion space.

In most cases t.e booster charge should be inhibited on its outer peripheral surface and at its end edges, so as to burn over the wh le of its inner tubular face and thus radially outwards and the second charge formed or packed within its particular container so that it willburn from one end to the other, that is to say, cigarette-wise. This inhibition of the booster charge may be effected by coating the aforesaid portions thereof with an inhibitor and/or sealing them against the wall of its particular 3,llh,3?7 Patented Jan. 21, F364 ice casing. In most cases, however, it is desirable to use an inhibitive coating.

The invention will now be described, by way of example, with reference to the accompanying drawings, of which:

FIG. 1 is a longitudinal section of one form of rocket according to the invention.

FTG. 2 is an end view.

In the construction shown in the drawings, the rocket comprises an outer tubular casing 1 having a thickened forward portion 2, which is interiorly screw-threaded at 3 to carry the rear end portion of an appropriately screwthreadcd warhead The rear end of the casing 1 is thickened at 5 and provided interiorly thereat with a screw-threaded portion 6 into which screws a sleeve 7 the rear end portion of which is interiorly screw-threaded at 3.

Fitting within the casing l is a tubular booster charge 9 provided upon its outer periphery and upon its end edges with a coating of inhibitor iii and retained axially within said casing between a disc ll, located against the inner end face of the warhead 4, and the forward edge of the sleeve 7.

Formed centrally upon the rear face of the disc 11 is a cup-shaped portion 12 in which fits the appropriately shaped centre portion of a cap l3 which is welded or otherwise suitably fixed within the forward end of a second tubular casing 14, the rear end of which casing is screwed into the forward end of a cup 15' formed integral with the central portion of a circular plate 16, which is screwed into the screw-threaded portion 3 of the sleeve '7.

The tubular casing 14 is of such external diameter as to form between itself and the interior surface of the booster charge 9 an annular passage 17, and carried withthe casing 14 is a charge llii, hereinafter referred to as the sustainer charge, which is provided upon its periphery with a coating of inhibitor 19, to ensure that said charge will burn cigarette-wise from its rear end.

The cup 15 is interiorly coned and the plate 16 is provided with a central port Ztl which communicates at its inner end with this cup, and into the outer end of which port is screwed a nozzle it through which can act the propulsive gases from the charge 13.

The peripheral portion of the plate 16 is provided with three screw-threaded perforations 22, which are equidistantly spaced, as shown in FIG. 2 and into each of which perforations is screwed a nozzle 23 through which can act the propulsive gases from the booster charge Q.

The nozzles 23 may, if required, be canted to provide spin stabilisation, in which case, the perforations 22 would, of course, be suitably drilled for this purpose.

We claim:

A rocket comprising a first outer tubular casing defining a thickened internally threaded forward portion and a thickened internally threaded rearward portion, a warhead threadably secured in said forward portion, a disc having an inwardly extending, axially disposed cup shaped portion abutting the rearward face of said warhead, a tubular booster charge having its outer peripheral and end surfaces coated with an inhibitor axially retained in said outer tubular casing, a second tubular casing coaxially arranged in said rocket, said second casing having a cap portion normally received in said cup shaped portion of said disc and a rearward threaded portion, the diameter of said second casing being substantially less than the inner diameter of said tubular booster charge to provide a uniform annular space therebetween, a solid explosive charge having its outer peripheral surface coated with an inhibitor filling said second casing, said charge being independent of said tubular charge, an externally threaded sleeve threadably engaging said rearward internally threaded portion of said outer casing, said sleeve 4 having an internally threaded rearward portion, a circular References Cited in the file of this patent externally threaded plate threadably engaging said rear- UNITED STATES PATENTS ward internally threaded portion of said sleeve, sald plate W having a forwardly extending internally threaded conical 2519183 13ml? 1950 cup, said cup being threadably secured to said rearward 5 2,703,900 muss 1955 threaded portion of said second casing, a centrally dis- 2,755,620 Glnot July 1956 posed nozzle in said plate, said nozzle communicating FOREIGN PATENTS with said conical cup and a plurality of symmetrically 5,099 Great Britain Dec 12 1878 arranged nozzles communicating with said annular space between said tubular booster charge and said inner casing. 10 

